IPv6. IPv4 & IPv6 Header Comparison. Types of IPv6 Addresses. IPv6 Address Scope. IPv6 Header. IPv4 Header. Link-Local

Transcription

1 1 v4 & v6 Header Comparison v6 Ver Time to Live v4 Header IHL Type of Service Identification Protocol Flags Source Address Destination Address Total Length Fragment Offset Header Checksum Ver Traffic Class Payload Length v6 Header Next Header Source Address Flow Label Hop Limit Options Padding Destination Address 2 v6 Address Scope Types of v6 Addresses Address assigned to interface Interface ID Addresses depend on scope Link Local Local hardware connection Broadcast domain Site Local Autonomous system (AS) Network of one organization Global Unicast One address on a single interface Delivery to single interface Multicast Address of a set of interfaces Delivery to all interfaces in set Anycast Address of a set of interfaces Delivery to closest single interface in set Global Site-Local Link-Local No broadcast addresses 3 4

2 5 v6 Address v6 Prefix 128-bit address 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses 50,000 addresses per square meter of land on Earth Prefix Format (PF) Binary Hex Type Application Colon-separated 16-bit hex 2031:0000:130F:0000:0000:09C0:876A:130B ::/8 0200::/7 Reserved address Reserved for ATM Not assigned Used in telephony Leading zeros optional 2031:0:130F:0:0:9C0:876A:130B Successive 0 fields written :: (once) ::/3 Aggregatable Global Unicast Address Aggregation of host addresses into networks and subnets legal illegal 2031:0:130F::9C0:876A:130B 2031::130F::9C0:876A:130B v4 compatible used in tunneling v6 through v4 0:0:0:0:0:0: = ::0102:0304 v4 mapped used by v6 source sending to v4 dest 0:0:0:0:0:FFFF: = ::FFFF:0102: FE80::/10 FEC0::/10 FF00::/8 Link Local Address Site Local Address Multicast Address Address hosts on LAN segment Addresses used with an AS (like in v4) Assigned to a group 6 Unicast Address Formats Hierarchical Addressing & Aggregation Link Local FP (10 bits) FE80::/10 Reserved (54 bits) MUST be 0 Interface ID (64 bits) MAC derived Customer :0410:0001:/48 ISP 2001:0410::/32 Site Local FP (10 bits) FEC0::/10 Global FP (3 bits) ::/3 Subnet (38 bits) ISP assigned (45 bits) Provider Administered Subnet (16 bits) Locally Administered Subnet (16 bits) Locally Administered Interface ID (64 bits) MAC derived Interface ID (64 bits) MAC derived or Locally Administered or Random Customer 2 v6 Internet 2001:0410:0002:/ ::/3 Authority Assigns 2001:0410::/32 to ISP ISP Assigns 2001:0410:1:/48 to customer 1 Assigns 2001:0410:2:/48 to customer 2 Customer 1 Assigns subnets 2001:0410:1:1/64, 2001:0410:1:2/64 7 8

3 9 Extension Headers Next header field Points to header following v6 header Upper Layer Protocol TCP Header UDP Header v6 Header Interdomain Routing Protocol Resource Reservation Protocol v6 ICMP Packet Extension headers Multiple of 8 bytes Syntax depends on option Headers (except 60) appear only once Option Header Hop by Hop Options Header v6 Routing Header v6 Fragment Header Encapsulating Security Payload v6 Authentication Header No Next Header Destination Options Header v6 Option Headers Tunneling Option 41 v6 in data field of v6 Example used with fragmentation when router adds option field Hop-by-hop header Options checked by every router and destination node Destination options header Options checked by destination node Routing header Source sets route through network Fragment header Handles fragmentation Authentication header / Encapsulating Security Payload Implement sec 10 Option Header Examples Traffic Class + Flow v6 Header Next = TCP v6 Header Next = Routing v6 Header Next = Routing v6 Header Next = Routing TCP Header + Data Routing Header Next = TCP Routing Header Next = Fragment Hop by Hop Header Next = Fragment TCP Header + Data Fragment Header Next = TCP Fragment Header Next = TCP TCP Header + Data Fragment TCP Header + Data Fragment DSCP 6 bits Differentiated Services Code Point Sets per-hop behavior according to service ECN 2 bits Explicit Congestion Notification Router can set congestion indication Flow Stream of related packets from 1 source to 1 destination Require particular handling by routers Requirements cached in routers Example real time priority 24 bit flow label Chosen randomly from 1 to FFFFF 0 not part of a flow Flow identified by label + src + dest 11 12

4 13 ICMPv6 ICMP Internet Control Message Protocol Offset Neighbor Discovery Identify hosts and routers on physical LAN segment Replaces ARP 0 32 Type Code (subtype) ICMP Message Checksum Address resolution Obtain MAC address for neighbors Destination Unreachable Packet Too Big Time (Hop Count) Exceeded Echo Request Echo Reply Group Membership Query Neighbor Solicitation Node sends ICMP neighbor solicitation message to host 4 Parameter Problem Group Membership Report Group Membership Reduction Router Solicitation 64 bit local link multicast prefix FF02:: 64 bit host address Interface ID Router Advertisement Neighbor Solicitation Neighbor Advertisement Neighbor advertisement Neighbor sends ICMP neighbor advertisement with MAC address 137 Redirect Message 14 Router and Prefix Discovery Stateful Auto Configuration Router advertisements Routers send ICMP messages to hosts on some schedule Addressed to FF02::1 Multicast address all systems on local link Provides configuration parameters MTU Global prefix address configuration method (ICMP / stateless) Router solicitation message Host sends ICMP message to request router service Addressed to FF02::2 Multicast address all routers on local link Routers respond with router advertisement DHCP service Similar to v4 DHCP messages Solicit Advertise Request Reply Release Reconfigure DHCP client Waits for DHCP advertisement Sends DHCP request DHCP server Sends DHCP reply Provides address + configuration parameters 15 16

5 17 Stateless Auto Configuration Node reads 48-bit MAC address from hardware Converts 6-byte MAC address to 8-byte node address 48-bit MAC address 24 bits FFEE 24 bits Example: FF EE Extends link-local prefix to 64 bits FE80::/10 FE80::/64 Attaches link-local prefix to node address Creates temporary link-local unicast address Example: FE80::1122:33FF:EE44:5566 Verifies unique address with neighbor solicitation No response to link-level address assigns address to interface Sends router solicitation Routers respond with router advertisement No response node attempts DHCP Response message provides parameters MTU, global prefix Replaces FE80::/64 global prefix to form global unicast address Mobile (RFC 2002) Internet protocol supporting host mobility Maintains TCP connections as host changes location Supports authentication Mobile host maintains single long-term address Version 4 address and address format are unaffected Routing tunnel replaces standard routing X X=1, 2, 3,..., 254 Router Router Y Y=1, 2, 3,..., Mobile Basic Idea Mobile Entities Similar to Call forwarding Mail forwarding at post office Mobile Node Permanent address Usual home service router Finds mobile service routers when roaming Home router and mobile service router coordinate s Sent to usual home router Forwarded by home router to mobile service router Forwarded to Mobile Node Mobile Node (MN) Host or router that can change its point of attachment Home Address Permanent address assigned to MN Correspondent Node (CN) Node that sends s to MN home address Home Agent (HA) Maintains table of registered mobile nodes Forwards s addressed to mobile node Foreign Agent (FA) Delivers s between MN and HA Mobility Agent HA or FA supporting mobility Care-of-Address (COA) FA address used to identify current location of MN 19 20

6 21 Agent Discovery Mobility Agents broadcast availability Home Agents (HA) Foreign Agents (FA) Mobile Node (MN) looks for Local router services when connected to home network Foreign Agent (FA) services when connected to foreign network Care of Address Discovery Mobile Node (MN) Requests service from Foreign Agent (FA) Foreign Agent Assigns Care-of-Address (COA) to MN FA can have 1 or more available COAs Usually FA assigns same COA to all MNs MN requests service from FA FA advertises services 22 Registration Foreign Agent Requests Mobile support from MN s Home Agent Home Agent Agrees to provide Mobile support MN Registers COA with its HA HA forwards s to FA Datagrams for MN arrive at HA Establishment of Service in Mobile MN registers with FA and HA FA forwards request to HA MN in home network FA informs MN of status HA accepts or rejects MN in foreign network 23 24

7 25 Mobile End to End Delivery Roaming and Hand Off From: HA address From: CN address To: FA COA Address To: MN Home Address Standard FA DATA HA Roaming MN Moves to new attachment point (network) Requires change of FA Multiple bindings Multiple COAs old + new Avoid loss Avoid too frequent registrations MN HA Forwards each packet to multiple COAs From: CN address To: MN Home Address DATA Standard From: CN address To: MN Home Address DATA CN MN Receives packet at one COA Route optimization after reconnection 26 Change of Foreign Agent CN HA FA old FA new MN registration MN changes location Triangle Routing Home agent is bottleneck Increases network load registration ACK update ACK 27 28

8 29 Route Optimization Roaming Under Route Optimization FA HA (2a) s (5) (4) Binding Update (2b) Warning (3) Binding Request (1) 30 v6 Mobile Implements Mobile 1. Mobile node (MN) obtains local address using autoconfiguration Roaming address = care-of-address (CoA) No special Foreign Agent 2. MN registers with Home Agent by sending Binding Update 3. HA forwards traffic for registered MN Tunnels packets from CN to MN 4. MN sends packets to CN directly 5. Route optimization HA provides CN with CoA 1 MN CN 3 HA v6 Mobility Support Node writes home address in destination option header Destination node can identify by home address Tunneling Using v6 routing extension headers instead of encapsulation Reduces processing cost of delivering packets Handover Node moves from ESS to ESS Layer 2 handover change AP and ESS ID Node detects change in on-link subnet prefix Updates CoA v6 Mobility header messages Home Test Init, Home Test, Care-of Test Init, and Care-of Test Binding Update / Acknowledgement MN to notifies node or HA of current binding 31 32